Risk: Medium
Vulnerabilities recently found in Yahoo! Messenger can be exploited by malicious people to compromise a user's system. The vulnerabilities are caused due to boundary errors within the YVerInfo.GetInfo.1 and YVerInfo.GetInfo2.1 ActiveX controls (YVerInfo.dll) when handling the "fvCom()" and "info()" methods. These can be exploited to cause stack-based buffer overflows by passing specially crafted, overly long arguments to the affected methods.
Successful exploitation can result in arbitrary code execution, but to be successful, a malicious web page must be in a domain that contains a ".yahoo." substring in the subdomain of the TLD. The vulnerabilities have been confirmed in versions downloaded before the end of August this year and can be patched by downloading the update to version 8.1.0.419 at:
http://messenger.yahoo.com/download.php.